Here are the top 10 facts on the coronavirus outbreak:
Wuhan, the city which is the epicentre of the outbreak, is under effective quarantine, with outward flights and trains suspended, and subways halted. Authorities have told people in the to not leave without a special reason.
The actual number of people infected by the coronavirus in Wuhan alone could be as high as 4,000, around 10 times the official figure, according to an estimate published by scientists at Imperial College London.
Thailand reported four cases, and South Korea, Japan, Taiwan and the United States one each. Patients in these cases were either residents of Wuhan or recent visitors to the city that is home to 11 million people.
Airports in the United States and Britain, as well as many Asian countries, including Japan, Thailand, Singapore and South Korea, stepped up screening of passengers from Wuhan. Russia strengthened sanitary and quarantine controls at entry points.
In India, the government has instructed Delhi, Mumbai, Kolkata, Chennai, Bengaluru, Hyderabad and Kochi airport officials to screen passengers coming from mainland China. The Indian embassy in China has been regularly providing the health ministry with updates on the status of the infected cases in the country, Health Secretary Preeti Sudan said.
Global health authorities fear the spread of the virus will accelerate as hundreds of millions of Chinese travel at home and abroad during the week-long Lunar New Year holiday.
The coronavirus has been named "2019-nCoV". Coronavirus is a family of viruses that can cause illnesses ranging from the common cold to Severe Acute Respiratory Syndrome (SARS), which killed 349 people in mainland China and another 299 in Hong Kong between 2002 and 2003.
The new strain of coronavirus may have originated in bats or snakes, according to genetic analysis of the virus, a study by Beijing's Chinese Academy of Sciences suggests. A second study published on Wednesday in the Journal of Medical Virology identifies snakes as the possible intermediate hosts.
Those infected could experience flu-like symptoms, including fever, a cough, shortness of breath, a sore throat or runny nose.
The World Health Organisation sent directives to hospitals around the world on infection prevention and control. The UN body will decide on Thursday whether to declare the outbreak a global emergency.
(With inputs from AFP, Reuters and PTI)